The best poker-faced liar may be discovered under a new lie detector test which, the developers say, can monitor tiny changes in facial expressions.
The test has been developed by British scientists using cameras and computer software to recognise when people are fibbing.
The system picks up give-away clues such as lip-biting, slips of the tongue, nose-wrinkling, and blinking.
A thermal imaging camera is also used to measure blushing and blood-flow patterns around the eyes which, researchers say, shows up untruthful exchanges.
The test could in future be used by police and border officials questioning suspect criminals or terrorists, its inventors suggest.
With hidden cameras positioned up to three metres away, suspects would not know they were being watched.
Conventional “polygraph” lie detector tests involve wiring up subjects to equipment that measures blood pressure, pulse, heart rate, respiration and electrical skin activity.
But people have been known to “beat” the test using a range of techniques, such as controlling breathing and heart rate.
“Our aim was to develop a purely non-invasive lie detector technology,” said Professor Hassan Ugail, who heads the University of Bradford team behind the new test.
“When a person is being deceitful, when a person lies, there is increased brain activity and this is reflected in the face through involuntary facial expressions and blood flow.”
The facial lie detector would never be a “fail-safe” method of spotting potential terrorists, he stressed, but it could provide a useful extra tool in the armoury of security officials.
“Border control officers are very good at spotting liars,” he said.
“This will be a decision aid for them.”
The professor also thinks the invention could be used to investigate potential illnesses.
Parkinson’s patients are known to have a limited range of facial expressions, he says and more subtle diagnostic clues might also be present in the faces of people with Alzheimer’s.
“If we could use facial expressions to detect dementia that would be something great.”
Source : Sky News